Heat transfer system



Jan. 19, 1937. D. B. KNIGHT 2,068,549

HEAT TRANSFER SYSTEM Filed May 25, 1933 2 Sheets-Sheet 1- IN V EN TOR.

0000/0 5, Knig/n TTORNEY Jan. 19, 1937.

D. B. KNIGHT 2,068,549

HEAT TRANSFER SYS TEM Filed May 23, 1933 2 Sheets-Sheet 2 INVENTOR.

ATTORNEY? Patented Jan. 19, 1937 UNITED STATES PATENT OFFICE 2,068,549 HEAT TRANSFER SYSTEM Donald B. Knight, Brooklyn, N. Y., minor, by mesne assignments, to Servel, Inc.. Dover, DeL,

a corporation of Delaware Application May 23, 1933, Serial No. 672,405 7 Claims. (01. 257-24) such as the condenser or the absorber of an absorption type refrigeration apparatus, to a cooling medium therebelow, as indicated in my Patent No. 1,846,006. Such examples are merely illustrative of the fields of utility of my present invention which, however, is not limited thereto,

but resides in a system which operates without the use of mechanical pumps, valves, or other moving parts and which may be employed to transfer heat from an object or area to be cooled to a cooling medium at a level lower than the object or area, or, broadly, the circulation of a heat transfer fluid by the addition of heat at one level and the removal of heat at a lower level.

It is an object of my invention to provide a system by which heat may be transferred a greater distance below the source thereof through the agency of a fluid which is circulated due to a force within the system produced only by the heating and cooling of the fluid therein.

It is a further object to provide such a system I attain these objects by providing a main condenser or heat radiator and a small condenser located at a higher level, these condensers being connected by a rising liquid conduit, the connec- 45 tion of this conduit to the main condenser being made through a liquid trap so that condensate in the main condenser is raised therethrough into the upper condenser due to a difierence in pressure between the condensers. A boiler or vaporizer is 50 connected for delivery of vapor to the lower main condenser and is located suficiently below the upper condenser for delivery of liquid from the latter by gravity through a liquid trap when the pressures in the boiler and upper condenser are equalized. Intermittent equalization of pressure is accomplished by a liquid seal which creates a liquid column suihcient to balance a pressure great enough to raise liquid from the lower main condenser to the upper condenser, but which is intermittently displaced when this pressure is exceeded.

The full nature of my invention together with the objects and advantages thereof will be apparent from the following description taken in connection with the accompanying drawings in which 1 boiler l0 and the supply of heat thereto is represented by a burner II. The upper part of the boiler is connected through conduit 12 to a con- 0 denser or radiator I3 located at a level below the boiler. The condenser is constructed with a liquid trap or collecting chamber it from the lower part of which a riser or pump pipe l5 extends upwardly to a second condenser I6 located 25 above the boiler it. The lower part of condenser it communicates with the boiler it through a trap shown as a U-tube I! having one leg extending into the upper part of the boiler. A second U-tube trap i8 is also provided between the con- 30 denser it and the boiler ill. As shown, the first trap i'l extends downwardly to a level slightly above the opening of the riser or pump pipe l5 in the collecting chamber i l and the second trap i 8 extends downwardly further than the trap i1 and has one leg opening into the boiler slightly above the corresponding opening of trap l7.

Assuming that liquid stands in the system to applied to the boiler causes the liquid therein to 40 vaporize, the vapor passing through conduit i 2 to the condenser it. Here the vapor is condensed and the liquid drains into the trap it where it seals the end of the riser or pump pipe l5. Since the pressure in the condenser i3 is sub-,- stantially the same as the pressure in the boiler it the condensate collected in trap it rises in the pipe it. At the same time, the liquid in the right hand leg of the U-tube traps I1 and it rises to a level which balances the liquid 001- umn in pipe I5. When the liquid level in the left hand leg of U-tube trap i1 is depressed until it reaches the bottom of said trap this trap blows, that is, the liquid in the right hand leg is forced upwardly into codenser l6 permitting vapor from boiler I0 until the liquid columns in column in riser pipe l5. Also by terminating one boiler 10 to pass directly to the condenser I16 thus equalizing the pressures in the system.

With the pressure thus equalized, liquid flows from condenser I6 through the U-tube trap IIB into the boiler in until the seal in trap I1 is reformed, and liquid is again pumped through pipe Hi from the trap M by the difference in pressures incondensers l3 and L6.

Thus, thejpressures in the boiler l0 and.-the upper condenser l6 are intermittently equalized. During the time that the pressures are equalized, that is when trap I1 is open, liquid flows by gravity from the upper condenser IE to the boiler l0 through the trap l8. When the trap I1 is again filled with liquid, as previously described, a pressure differential again builds up between the boiler l0 and the upper condenser l6, since no more vapor is delivered to the condenser l6 and the residue vapor therein condenses to liquid. As the pressure differential builds up, liquid rises in conduit l5 and is correspondingly depressed in the left hand legs of the traps l1 and I8, as

previously described, the liquid columns in traps I1 and I8 and in conduit 15 balancing each other. It will be understood from the above description that the depth of the trap l1 must be sufficient to permit the liquid column in conduit l5 to rise high enough to overflow into the upper condenser i6 before the trap l1 blows. That is, liquid should reach the upper end of the conduit l5 just as vapor from the boiler approaches the bottom of the trap l1, so that liquid is intermittently spilled into the upper condenser 16 just prior to the intermittent blowing of the trap ll, whereby liquid is intermittently pumped from the lower condenser or radiator l3 to the upper condenser l6, as previously described.

An important result of the above described doubletrap arrangement is that liquid will flow from condenser i6 through trap l8 into the trap ll is reformed and the traps ll and i8 balance the leg of the trap I! in the bottom of condenser l6 if any vapor should be pocketed when the seal in trap I1 is re-formed this vapor condenses and is replaced by liquid from condenser is thereby insuring a liquid column which will counterbalance the column of liquid in riser l5 during the pumping cycle.

It will be understood that the above described heat transfer system may be utilized for either heating or cooling purposes. For instance, the boiler l0 may be the boiler of a steam heating plant and the main condenser l3, a radiator which it is desired should be located in a basement or other locality below the level of the boiler. In such case the system would be supplied with water as the heat transfer fluid which is vaporized in the boiler i0 and condensed in the radiator 13 in the manner previously described, the heat of condensation being radiated to increase or maintain the temperature of the locality to be heated. It maybe that it is desired to transfer heat from a heat rejecting element represented in the drawings by the burner H, for instance, the condenser of a refrigeration apparatus located in the upper part of a refrigerator cabinet where it is inaccessible for cooling by direct contact with air. In such instance the heat transfer system 'may be supplied with a suitable fluid such as methyl chloride, and the boiler or vaporizer l0 arranged in thermal exchange relation with the condenser to be cooled. In accordance with this invention the condenser or i the lower condenser,

radiator l3 may be located at the bottom of the refrigerator cabinet.

Figs. 2 and 3 show the above described liquid columns under two conditions in operation of the system. Referring to Fig. 2, liquid has just reached the upper end of the riser conduit I5 and has started to flow toward the upper condenser 16. Since the pressures in the boiler l0 and condenser l3 are substantially the same, liquid has been depressed in the traps l1 and I8. H indicates the height of the column of liquid in conduit l5, and H indicates the height of the liquid columns in the traps I1 and IS. The liquid columns H and H are equal and balance each other. Under these conditions, liquid has started to flow from the upper end of conduit l5 toward the upper condenser l6, and liquid has not yet reached the bottom of the shorter trap l1.

The liquid which flows into the upper condenser Hi from the upper end of conduit I5 is replaced by liquid from the sump M. The liquid level thus goes down in the sump 14. When the liquid level in the sump M has decreased an amount h, indicated in Fig. 3, the liquid column in conduit l5 has increased to a height H During this time, liquid has been added to that in the upper condenser Hi from the conduit l5. Also, liquid has been forced upwardly in the right hand legs of the traps I1 and I8 due to depression of liquid in the left hand legs of these traps a distance h The liquid level in the upper condenser I6 therefore increases by a height 71 This results in a new height of the liquid columns in the traps l1 and I8. This new height is indicated by H in Fig. 3. Again, the liquid columns H and H must be equal to each other. The liquid column 1-1 in Fig. 3 is higher than the liquid column H in Fig. 2 by the distance it in Fig. 3. The liquid columns H in Fig. 3 are higher than the liquid columns H in Fig. 2 by the sum of the distances h and 71. indicated in Fig. 3. The sum of the distances h. and h. is equal to the distance h.

It will be seen in Fig. 3 that liquid has reached the bottom of the equalizing trap H, but has not yet reached the bottom of either the permanent trap I8 or the bottom of the riser conduit I5 in the sump Ii. At this point, as well known, the equalizing trap i'i blows, that is, vapor forces liquid up the right hand leg of this trap and opens communication between the vapor spaces of the boiler l0 and the upper condenser l6.

When the pressures are equalized, as described, liquid drops back through conduit l5 into the sump M and liquid flows by gravity from the upper condenser l6 through the permanent trap I8 into the boiler l0, until the liquid seal in trap H is reformed, and the process is repeated as long as heat is applied to the boiler Hi.

It will be obvious to those skilled in the art that various other changes may be made in the construction and arrangement without departing from the spirit of the invention and therefore the invention is not limited to what is shown in the drawings and described in the specification but only as indicated in the following claims.

I claim:

1. In a fluid heat transfer system, a boiler, a condenser below said boiler having a liquid collecting chamber, a condenser above said boiler, a conduit from the upper part of said boiler to a liquid lift conduit from the collecting chamber in said lower condenser to said upper condenser, a U-tube liquid trap having one leg connected to the bottom of said 2,068,549 3 upper condenser and the other leg open into the said boiler and said upper condenser adapted to open into the upper part of said boiler above the 6. The method 01' circulating heat-conducting opening of said first trap, said second trap exfluid in a closed heat transfer circuit comprising tending below said first trap. applying heat to one portion of the system to n a fluid h ra f r y m, n pp vaporize a liquid, condensing the resulting vapor the pressure in the latter. displacing said column to equalize the pressures 3. In a fluid heat transfer system, a lower conresponsive to a predetermined pressure difference, denser, an upper condenser, a liquid lift conduit conducting liquid from the upper condenser to between said condensers, a boiler connected from the heated portion of the system while the presits vapor space to said lower condenser, means sures are equalized, and again establishing said for intermittently relieving the pressure in the liquid column. boiler, and means for re-fllling the boiler with 7. In a closed fluid heat transfer system, the liquid during the period that the pressure therein method of circulation which comprises vaporizis relieved. ing liquid by the addition of heat, condensing D condenser,alower condenser,aliquid lift conduit said upper portion to the heated portion by 35 between said condensers, a boiler connected from gravity. its vapor space to said lower condenser, and valve DONALD B. KNIGHT. 

